// 高德坐标系转天地图坐标系
var PI = 3.14159265358979324;

function transformLat(x, y) {
	var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
	ret += (20.0 * Math.sin(6.0 * x * PI) + 20.0 * Math.sin(2.0 * x * PI)) * 2.0 / 3.0;
	ret += (20.0 * Math.sin(y * PI) + 40.0 * Math.sin(y / 3.0 * PI)) * 2.0 / 3.0;
	ret += (160.0 * Math.sin(y / 12.0 * PI) + 320 * Math.sin(y * PI / 30.0)) * 2.0 / 3.0;
	return ret;
}

function transformLon(x, y) {
	var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
	ret += (20.0 * Math.sin(6.0 * x * PI) + 20.0 * Math.sin(2.0 * x * PI)) * 2.0 / 3.0;
	ret += (20.0 * Math.sin(x * PI) + 40.0 * Math.sin(x / 3.0 * PI)) * 2.0 / 3.0;
	ret += (150.0 * Math.sin(x / 12.0 * PI) + 300.0 * Math.sin(x / 30.0 * PI)) * 2.0 / 3.0;
	return ret;
}

function gcj02ToWgs(lng, lat) {
	var a = 6378245.0;
	var ee = 0.00669342162296594323;
	var lat1 = +lat;
	var lng1 = +lng;
	var dlat = transformLat(lng1 - 105.0, lat1 - 35.0);
	var dlng = transformLon(lng1 - 105.0, lat1 - 35.0);
	var radlat = lat1 / 180.0 * PI;
	var magic = Math.sin(radlat);
	magic = 1 - ee * magic * magic;
	var sqrtmagic = Math.sqrt(magic);
	dlat = (dlat * 180.0) / ((a * (1 - ee)) / (magic * sqrtmagic) * PI);
	dlng = (dlng * 180.0) / (a / sqrtmagic * Math.cos(radlat) * PI);
	var mglat = lat1 + dlat;
	var mglng = lng1 + dlng;
	var latlng = [];
	latlng[0] = lng1 * 2 - mglng;
	latlng[1] = lat1 * 2 - mglat;
	return latlng;
}
